[Wien] surface calculations convergence

[yvon billa]

Dear Wien2k users,
 I am a fairly new user of the Wien2k code trying out
some
calculations of surface.
First of all I choose  the following parameters :
9kpoint, Rkmax=7,
Gmax=14. Gradually I increased the vacuum region and I
get the
follwing results :

vacuum=18 Bohr->(ERy=-34203.340100, EFermi=-0.01240,
ELS_POTZ(0;0.5)=0.29376; 0.29376)
vacuum=20 Bohr->(ERy=-34203.397248, EFermi=-0.04518,
ELS_POTZ(0;0.5)=0.28243; 0.28243)
vacuum=22 Bohr->(ERy=-34203.365672, EFermi=-0.06347,
ELS_POTZ(0;0.5)=0.27183; 0.27183)
vacuum=24 Bohr->(ERy=-34203.275210, EFermi=-0.08632,
ELS_POTZ(0;0.5)=0.26200; 0.26200)
vacuum=26 Bohr->(ERy=-34203.151402, EFermi=-0.09458,
ELS_POTZ(0;0.5)=0.25277; 0.25277)
vacuum=30 Bohr->(ERy=-34202.840131, EFermi=-0.10152,
ELS_POTZ(0;0.5)=0.23607; 0.23607)
vacuum=32 Bohr->(ERy=-34202.677126, EFermi=-0.10785,
ELS_POTZ(0;0.5)=0.22849; 0.22849)

As you can see, surface properties or the potential in
the middle of
the vacuum increas with vacuum thickness and I think
that 32 Bohr is
a big value ! Can some one indicate me an idea about
the choice of a
good thickness values which can manage calculation
effort ?   

Thank you in advancve

Yvon Billa



		
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